Sort scala arrayBuffer of TimeStamp

Question

I have this function:

def getTime() : ArrayBuffer[Timestamp] = {
    val offset = Timestamp.valueOf("2015-01-01 00:00:00").getTime()
    val end = Timestamp.valueOf("2015-01-02 00:00:00").getTime()
    val diff = end - offset + 1

    val mList = ArrayBuffer[Timestamp]()

    val numRecords = 3
    var i = 0
    while (i < numRecords) {
      val rand = new Timestamp(offset + (Math.random() * diff).toLong)

      mList += rand
      i += 1
    }

  //  mList.toList.sortWith(_ < _); 
   // scala.util.Sorting.quickSort(mList.toArray);
}

I have tried to sort the array but could not. I get this error:

No implicit Ordering defined for java.sql.Timestamp.

I know I need to define how the ordering would be done. Is there a way to sort it easily as in Java: Collections.sort(list); or there is a better approach using Scala?

Answer 1

Alternatively, define it somewhere in your class and you're good to go:

implicit def ordered: Ordering[Timestamp] = new Ordering[Timestamp] {
    def compare(x: Timestamp, y: Timestamp): Int = x compareTo y
}
getTime().sorted // now this will work just fine

Answer 2

mList.sortWith(_.compareTo(_) < 1)

Note that's with an anonymous function, you could pass an explicit function, which would look like this:

def comparator(first: Timestamp, second: Timestamp) = first.compareTo(second) < 1

mList.sortWith(comparator)

There's no implicit ordering on Timestamp itself, here we're just sorting using the compareTo method.

Thanks to @Nick for pointing out sorting on getTime() wasn't suffient in all scenarios. I also looked at the before method which you would expect to work, but this only compares using the epoch value as well.